This invention relates to a distributed system comprising a document server and a plurality of clients which are connected to the document server via a network and, more particularly, to a method of managing a document shared in the distributed system.
In prior art, various proposals are already made as regards technique for permitting the plurality of clients carrying out an editing operation for the same document. By way example, a document managing method (which will be herein called a first prior art) is disclosed in Japanese Unexamined Patent Publication of Tokkai (JP-A) No. 7-85020 (which will be herein called a first reference) on Mar. 31, 1995. In the first prior art according to the first reference, a plurality of clients share the same document in a document data base on a server. On simultaneously carrying out the editing operation on the same document by the plurality of clients, the document as an editing object is copied to a document work file for each client. As a result, each client simultaneously carries out the editing operation on the document without affecting other clients. However, in the first prior art according to the first reference, it is difficult for each client to confirm edited contents in other clients. This is because the same document is copied to the document work file for each client and the editing operation is independently carried out by each client. As a result, it is difficult for a plurality of clients to work in cooperation with the edited contents mutually confirmed for the same document.
In addition, a computer conference device (which will be herein called a second prior art) is disclosed in Japanese Examined Patent Publication of Tokkou (JP-B) No. 7-50884 (which will be herein called a second reference) on May 31, 1995. In the second prior art according to the second reference, each client is provided with a document file for storing the same contents. When a plurality of clients simultaneously refer and renew a document in the document file, an editing command, etc. generated by each client are transmitted to a server and the server unanimously transmits the editing command, etc. to all of the clients to make all of the clients process the editing command, etc. With this structure, it is possible to carry out the editing operation for the same document with edited results confirmed by all of the clients.
In the second prior art according to the above-mentioned second reference, it is possible to proceed with group work with edited contents for each client confirmed by all of the clients. This is because, when the editing operation is carried out by any client, the editing operation is delivered to all of clients via the server so that the document of each client is edited in the similar manner in other clients. However, the second prior art according to the second reference is disadvantageous in that it is impossible to carry out access control for each portion composing the document so as to make a particular client see a portion in the document. Such access control is required on carrying out the group work by a plurality of clients. In this sense, the second prior art according to the second reference is still insufficient for applying to a distributed cooperation system.
Furthermore, a document database-based system (which will be herein called a third prior art) is known. Such a document database-based system is, for example, Notes which is developed by Lotus Development Corporation in U. S. A. In the third prior art, the same document is referred to a document structure defined by predetermined document components via an application program on the basis of the document structure. In addition, writing is simultaneously carried out for different document components (portions of the document) in the same document. Furthermore, in order to prevent data destruction by simultaneous access to the same portion in the same document, an access limitation is made on the basis of a lock used by a conventional database technique.
In the third prior art, if structure of the document is defined as a unit each of the predetermined document components, it is possible to carry out the access control so as to refer or modify the portion (the document component) in the document. From this point of view, the third prior art is most adapted for a group work system among the above-mentioned three prior arts. However, performing of such an access control is restricted to each unit or each of the predetermined document components. As a result, it is impossible for the third prior art to carry out the access control as regards, as a unit, a document component which will be prepared from now. Specifically, the third prior art can carry out, for the document having a structure which is designed the document so as to share by all of the clients, the access control on the portion defined as the document component but the third prior art cannot dynamically generate, in the document, a memorandum for private use or another memorandum which should like to make particular clients see that satisfy a particular condition. This is because, for that purpose, an area playing a role in the memorandum must be preliminarily prepared on definition of the document structure. In general, the required area for the memorandum depends on progress of the group work. As a result, it is difficult to preliminarily prepare the required area on definition of the document structure.
Various other distributed systems are already known. By way of example, a system and method for document database retrieval (which will be herein called a fourth prior art) is disclosed in Japanese Unexamined Patent Publication of Tokkai (JP-A) No. 8-77201 (which will be herein called a third reference) on Mar. 22, 1996. The fourth prior art according to the third reference improves the productivity, maintainability, etc., of an application program by enabling standardized access to a document database consisting of a main text file and bibliographical information by a standard database language.
A ciphered file sharing method (which will be herein called a fifth prior art) is disclosed in Japanese Unexamined Patent Publication of Tokkai (JP-A) No. 6-17505 (which will be herein called a fourth reference) on Jun. 24, 1994. The fifth prior art according to the fourth reference reduces management information even at the time of enciphering plural files by different keys by giving a hierarchical reference premission to a user, in the sharing method of a ciphered file.
A file sharing system between system (which will be herein called a sixth prior art) is disclosed in Japanese Unexamined Patent Publication of Tokkai (JP-A) No. 6-83691 (which will be herein called a fifth reference) on Mar. 25, 1994. The sixth prior art according to the fifth reference shares files between plural systems by accessing the files present in the respective system on a network at an application software level by a server for accessing the files based on requests from the users of the respective systems.
A method for sharing file by utilizing network of distributed system (which will be herein called a seventh prior art) is disclosed in Japanese Unexamined Patent Publication of Tokkai (JP-A) No. 6-68044 (which will be herein called a sixth reference) on Mar. 11, 1994. The seventh prior art according to the sixth reference reduces the communication processing overhead for file access request and file information transfer in each processing node and a file management node and to shorten the time required for access from each processing node to a shared file.
A system operation method for shared disk device (which will be herein called an eighth prior art) is disclosed in Japanese Unexamined Patent Publication of Tokkai (JP-A) No. 7-319828 (which will be herein called a seventh reference) on Dec. 8, 1995. The eighth prior art according to the seventh reference improves a restoration ratio in transaction unit at the time of generating a fault by excluding the restriction of access to a shared file to be accessed from plural application programs in plural processing systems.
At any rate, each of the first through the eighth prior arts is not useful at all or insufficient in a case of applying to the distributed cooperation system where a plurality of clients carry out group work.
It is therefore an object of this invention to provide a distributed system and a document sharing management method which are capable of assigning an access limitation on generation of a new component for a document.
It is another object of this invention to provide a distributed system and a document sharing management method of the type described, which are capable of editing a portion of the same document of the same contents by all of clients.
It is still another object of this invention to provide a distributed system and a document sharing management method of the type described, which are capable of editing another portion of the same document by particular clients or a particular group only.
It is yet another object of this invention to provide a distributed system and a document sharing management method of the type described, which are capable of utilizing a still another portion of the same document as a memorandum for private use.
Other objects of this invention will become clear as the description proceeds.
A situation to which this invention is applicable is for managing a document shared in a distributed system comprising a document server and a plurality of clients which are connected to said document server via a network.
According to an aspect of this invention, the above-mentioned method comprises the step of transmitting, from each client to the document server, an original transaction with information indicative of at least one client which uses a document.
The above-mentioned method further may comprises the steps of receiving the original transaction in the document server, of processing, in the document server, the original transaction as a global transaction to produce a document object, and of transmitting, from the document server to the at least one client, the global transaction as a local transaction. The above-mentioned method further may comprises the steps of receiving the local transaction in the at least one client, and of performing, in the at least one client, the local transaction to produce a virtual document object corresponding to the document object.
A distributed system to which this invention is applicable comprises a document server and a plurality of clients which are connected to the document server via a network.
In the distributed system according to an aspect of this invention, each of the plurality of clients comprises means for transmitting, to the document server, an original transaction with information indicative of at least one client which uses a document.
In the afore-mentioned distributed system, the document server preferably may comprise means for receiving the original transaction, means for processing the original transaction as a global document generation transaction to produce a document object, and means for transmitting, to the at least one client, the global transaction as a local transaction.
In the afore-mentioned distributed system, the at least one client preferably may comprise means for receiving the local transaction and means for performing the local transaction to produce a virtual document object corresponding to the document object.
A recording medium to which this invention is applicable is for use in a distributed system comprising a document server and a plurality of clients which are connected to the document server via a network.
According to a first aspect of this invention, the above-mentioned recording medium is for recording a first program to make each of the plurality of clients execute the procedure of transmitting, to the document server, an original transaction with information indicative of at lest one client which uses a document. Desirably, the abovementioned recording medium further may record a second program to make the document server execute the procedures of receiving the original transaction, of processing the original transaction as a global transaction to produce a document object, and of transmitting, to the at least one client, the global transaction as a local transaction. Desirably, the above-mentioned recording medium further may record a third program to make the at least one client execute the procedures of receiving the local transaction and of performing the local transaction to produce a virtual document object corresponding to the document object.
According to a second aspect of this invention, a recording medium records a program to make a client execute the procedure of transmitting, to a document server, an original transaction with information indicative of at least one client which uses a document. The document server may transmit a local transaction to the at least one client. In this event, the above-mentioned recording medium preferably further may record an additional program to make the client execute the procedures of receiving the local transaction and of performing the local transaction to produce a virtual document object corresponding to a document object generated in the document server.
According to a third aspect of this invention, a recording medium records a program to make a document server execute the procedures of receiving, from each client, an original transaction with information indicative of at least one client which uses a document, of processing the original transaction as a global transaction to produce a document object, and transmitting, to the at least one client, the global transaction as a local transaction.